American astronauts Michael S. Hopkins and Richard A. Mastracchio are being assisted by Japanese astronaut Koichi Wakata, who is using a robotic arm from inside the space station to help the astronauts during repairs. The space suits on the International Space Station, and specifically the one being worn by Mastracchio, have come under scrutiny after a near-fatal accident in July where an Italian astronaut almost drowned during a spacewalk. Officials have attributed the problem to the suit's cooling system, where they found that a filter had become clogged. The astronaut hurried back inside the space station, but not before water had blocked his nostrils.

To deal with possible drowning in space, both astronauts are wearing snorkels in case their space suits malfunction again.

NASA has taken other measures to ensure safety:

An absorbent pad installed in the back of the helmet can hold 20 to 27 ounces, or about 600 to 800 grams, of water. The astronauts will periodically tilt their heads back to check if the pads have become "squishy."

NASA had planned on sending a replacement space suit before the next space walk, but rising ammonia levels in the station made today's space walk a necessity.